The invention relates generally to relates to an apparatus to cloak objects large and small from electromagnetic radiation. In particular, the invention relates to an electromagnetic cloak having plates adjacently disposed at a separation distance.
Due to the ever increasing use of electromagnetics, the United States armed forces need methods to prevent electromagnetic interference. Preventing electromagnetic interference is also useful in the private sector. The physical implementation of an electromagnetic cloak is a relatively new idea, although the basic physics of electromagnetism has been long known. An electromagnetic cloak can conceal an interior object to electromagnetic radiation by not disturbing the electromagnetic field outside of the cloak in a detectable way. Such a cloak can be used anywhere there is an object that interacts with an electromagnetic wave.
In order to cloak an object, radiation must travel around the object and reconstruct on the other side in both phase and amplitude. The path around an object, embedded in free space, for example, is longer than the path radiation would take in free space if the object were not there. Free space radiation travels at the speed of light, and so the velocity of the wave taking the longer path must travel faster than the speed of light so the phase can reconstruct on the other side. The wave velocity denoted constitutes the phase velocity, which can travel faster than the speed of light without violating physical laws because there is no energy moved by phase velocity.
In a true cloak, the radiation is generalized to any polarization and frequency, and can originate from any origin. Scattered waves are non-existent and transmitted waves are not distorted in either phase or amplitude outside the cloak. The cloak behavior would not depend on the electromagnetic nature of the object being cloaked. There exists no known physically realizable cloak that can accommodate all these generalizations simultaneously. Therefore, a need exists for an effective electromagnetic cloak that can prevent electromagnetic interference.